BERLIN (Reuters) - Thieves have stolen the iron gate to Dachau concentration camp bearing the Nazi slogan "Arbeit macht frei" (work sets you free), the director of the memorial site in southern Germany and local police said on Monday.

The cast iron gate measures 190 cm by 95 cm and police said the thieves probably used a vehicle to flee with it on Saturday night.

"It is the central symbol of the prisoners' suffering at Dachau concentration camp and therefore has hit the memorial at its heart," said Gabriele Hammermann, director of the memorial. Prisoners passed it every day, she said.

The Nazis set up the camp in Dachau, near Munich, in 1933, only weeks after Adolf Hitler took power. Initially meant to detain political rivals, it became the prototype for a network of concentration camps where 6 million Jews were murdered, as well as Roma, Russians, Poles and homosexuals.

More than 200,000 people had been detained in the camp by the time US troops liberated it in 1945. Television images showing piles of bodies and starved inmates of the camp were among the first scenes the world saw of the Holocaust.

In December 2009 the "Arbeit macht frei" sign was stolen from the entry gate of the former Nazi death camp of Auschwitz in Poland, by a Swedish man with far-right ties.

He was sentenced a year later by a Polish court to nearly three years for masterminding the theft, while two Poles were jailed for up to 2-1/2 years for snatching it and cutting it into pieces to fit into their car.